Reversible flow evaporator system

ABSTRACT

A reversible flow heat exchange system includes a heat exchanger system that includes a canister configured to receive a first fluid from a machine and a heat exchanger disposed within the canister. The reversible flow heat exchange system also includes a cooling system coupled to the heat exchanger and configured to circulate a second fluid between the heat exchanger system and the cooling system and a reversing valve coupled to the heat exchanger and configured to selectively direct a flow of the first fluid in a first direction through the canister and in a second direction through the canister that is opposite the first direction.

TECHNICAL FIELD

The present invention relates generally to a heat exchange system andmore particularly, but not by way of limitation, to a system and methodfor reversing a flow of a fluid through the heat exchange system.

BACKGROUND

Machines often make use of a circulating fluid (e.g., oil) to providelubrication and/or cooling. As the fluid circulates through the machine,heat is dissipated. The dissipation of heat from the machine may beimproved by circulating the fluid from the machine to an externalcooling apparatus, such as a heat exchanger. Examples of such machinesinclude lathes, CNC machines, mills, and other machines that use acutting tool to shape metallic objects. As the cutting tool removesmetal via cutting or abrasion, heat is generated as a result of the workthat is done to the metallic object by the cutting tool. The heatgenerated can damage the cutting tool, the machine, and/or the metallicobject being worked on. In order to remove this generated heat, a fluidcan be circulated around the cutting tool and the metallic object toabsorb heat. Removal of heat from the machine can be improved bycirculating the fluid through a cooling system.

While using a cooling system can be beneficial, the external coolingsystem can become clogged by debris that collects within the fluid as aresult of the cutting/abrasion process. For example, the debris caninclude metal shavings, cuttings, particles, dust, sludge, and the like.The debris may include other particulate matter that the fluid isexposed to during operation of the machine. As the machine and coolingsystem operate, elements of the cooling system (e.g., an evaporator) cancollect debris. As debris builds, efficiency of the cooling systemdeclines. Eventually, it becomes necessary to cease operation of thecooling system so that maintenance and cleaning can take place.

BRIEF SUMMARY OF THE INVENTION

An illustrative reversible flow heat exchange system includes a heatexchanger system that includes a canister configured to receive a firstfluid from a machine and a heat exchanger disposed within the canister.The reversible flow heat exchange system also includes a cooling systemcoupled to the heat exchanger and configured to circulate a second fluidbetween the heat exchanger system and the cooling system and a reversingvalve coupled to the heat exchanger and configured to selectively directa flow of the first fluid in a first direction through the canister andin a second direction through the canister that is opposite the firstdirection.

An illustrative method of controlling a direction of fluid flow througha heat exchanger system includes circulating a first fluid between amachine and a heat exchanger system, circulating a second fluid betweenthe heat exchanger system and a cooling system, directing a flow of thefirst fluid through the heat exchanger system in a first direction byorienting a reversing valve in a first orientation and directing theflow of the first fluid through the heat exchanger system in a seconddirection by orienting the reversing valve in a second orientation, andexchanging, via a heat exchanger of the heat exchanger system, heatbetween the first fluid and the second fluid. The method furtherincludes wherein a direction of flow of the first fluid through themachine remains the same when the first fluid flows through the heatexchanger system in the first or the second directions.

An illustrative reversible flow heat exchange system includes a heatexchanger system that includes a canister configured to receive a firstfluid from a machine and a heat exchanger disposed within the canister.The reversible flow heat exchange system also includes a cooling systemcoupled to the heat exchanger system and configured to circulate asecond fluid between the heat exchanger system and the cooling system, areversing valve coupled to the heat exchanger and configured toselectively direct a flow of the first fluid in a first directionthrough the canister and in a second direction through the canister, anactuator coupled to the reversing valve and configured to control anorientation of the reversing valve, a controller configured to operatethe actuator and a sensor coupled to the controller and positioned tomonitor build up of particulate matter on the heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a prior art heat exchange system;

FIGS. 2A and 2B illustrate a reversible flow heat exchange systemaccording to aspects of the disclosure;

FIG. 3 illustrates a heat exchanger for use with the reversible flowheat exchange system of FIGS. 2A and 2B according to aspects of thedisclosure; and

FIG. 4 is a flowchart illustrating a method of using a reversing valvein accordance with aspects of the disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment(s) of the invention will now be described more fully withreference to the accompanying Drawings. The invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiment(s) set forth herein. The invention should only beconsidered limited by the claims as they now exist and the equivalentsthereof.

FIG. 1 illustrates a prior art heat exchange system 100. System 100includes a machine 102, a heat exchanger system 104, and a coolingsystem 106 and provides cooling for machine 102 by circulating a firstfluid between machine 102 and heat exchanger system 104 via fluid lines108, 110. The first fluid flows from machine 102 to heat exchangersystem 104 via fluid line 108 and returns to machine 102 via fluid line110. The first fluid absorbs heat from machine 102 and then transfersthe absorbed heat to a second fluid via a heat exchanger 112 within acanister 114 of heat exchanger system 104. The second fluid circulatesbetween heat exchanger system 104 and cooling system 106 via fluid lines116, 118. Heat is removed from the second fluid by cooling system 106.Cooling system 106 can cool the second fluid in a variety of ways. Insome aspects, cooling system 106 includes traditional air conditioningcomponents, such as a compressor and a condenser, with heat exchanger112 being used like an evaporator to cool the first fluid. In otheraspects, cooling system 106 can cool the second fluid using other knowncooling methods.

System 100 can be effective for removing heat from machine 102. However,the ability of system 100 to remove heat from the first fluid candecline over time due to buildup of particulate matter on heat exchanger112. Particulate matter becomes entrained in the first fluid as thefirst fluid passes through machine 102 and is carried with the firstfluid to heat exchanger system 104. The particulate matter may be, forexample, metal shavings, cuttings, particles, dust, sludge, and the likethat results from operation of machine 102. The first fluid enters heatexchanger system 104 and is introduced to a first side 120 of canister114. The first fluid then flows around heat exchanger 112 (i.e., throughgaps 136, see FIG. 3) to a second side 122 of canister 114. As the firstfluid flows around heat exchanger 112, some of the particulate matterwithin the first fluid is deposited upon surfaces of heat exchanger 112.As more and more particulate matter is deposited upon heat exchanger112, the efficiency of heat transfer between the first fluid and thesecond fluid decreases. In some instances, flow of the first fluidthrough heat exchanger system 104 is reduced or even blocked.

The build up of particulate matter on heat exchanger 112 can be delayedsomewhat by filtering the first fluid before the first fluid enters heatexchanger system 104. However, use of a simple filter only slows thebuildup of particulate matter and does not prevent it entirely.Eventually, it becomes necessary to cease operation of heat exchangersystem 104 to perform maintenance. Maintenance requires disassembly ofheat exchanger system 104 so that heat exchanger 112 can be cleaned.Cleaning heat exchanger 112 is time consuming as numerous fluidconnections (e.g., fluid lines 108, 110, 116, 118) to heat exchangersystem 104 must be disconnected. In some aspects, the second fluid maybe a refrigerant under pressure, which makes connecting anddisconnecting heat exchanger 112 more difficult. Using more complexfiltering systems may remove more particulate matter from the firstfluid, but more complex filtering systems are undesirable as their useadds complexity and cost to system 100.

Referring now to FIGS. 2A and 2B, a reversible flow heat exchange system200 is illustrated. Reversible flow heat exchange system 200 includessome of the same components of system 100 of FIG. 1. Components thatremain the same in FIG. 2 have the same part number as shown in FIG. 1.A primary difference between reversible flow heat exchange system 200and system 100 is the inclusion of a reversing valve 202 that includes afirst pair of openings A-A′ and a second pair of openings B-B′. Eachpair of valve openings are coupled together so that the first fluidflows from one valve opening of the pair of valve openings to the othervalve opening of the pair of valve openings. For example, fluid thatenters a first valve opening A flows through reversing valve 202 andexits reversing valve 202 through a second valve opening A′. Relative toFIG. 1, reversing valve 202 is placed in-line between fluid lines 108,110 and allows the direction of flow of the first fluid around heatexchanger 112 to be reversed. As illustrated in FIGS. 2A and 2B, system100 may be modified so that fluid line 108 is split into fluid lines 204and 206 and fluid line 110 is split into fluid lines 208 and 210. Inother aspects, fluid lines 108, 110 may be removed and new fluid lines204-210 can be installed in their place. Fluid line 204 directs thefirst fluid out of machine 102 and fluid line 208 directs the firstfluid into machine 102.

With reversing valve 202 oriented as shown in FIG. 2A (i.e., the firstpair of valve openings A-A′ are connected to fluid lines 204, 206,respectively, and the second pair of valve openings B-B′ are connectedto fluid lines 210, 208, respectively), the first fluid flows from firstside 120 to second side 122 (i.e., in the same direction as shown inFIG. 1). Rotating reversing valve 202 90° to the right results in theorientation of reversing valve 202 as shown in FIG. 2B (i.e., the firstpair of valve openings A-A′ are connected to fluid lines 210, 204,respectively, and the second pair of valve openings B-B′ are connectedto fluid lines 208, 206, respectively). With reversing valve 202oriented as shown in FIG. 2B, the first fluid flows from second side 122to first side 120 (i.e., in a direction opposite to that shown in FIG.1). It is noted that regardless of the configuration of reversing valve202, the first fluid flows through machine 102 in the same direction.

FIG. 3 is a perspective view of heat exchanger 112. FIG. 3 is discussedrelative to FIGS. 2A-2B. Heat exchanger 112 is a microchannel heatexchanger that includes a first end tank 124 and a second end tank 126that are joined together by a plurality of microchannels 128. Duringoperation of reversible flow heat exchange system 200, the second fluidenters heat exchanger 112 via an inlet 130 coupled to first end tank124. First end tank 124 is divided into two sections by a baffle 132.The second fluid is distributed by first end tank 124 into a first setof microchannels of the plurality of microchannels 128. The second fluidnext enters second end tank 126 and is directed back to first end tank124 by a second set of microchannels of the plurality of microchannels128. The second fluid then exits heat exchanger 112 via an outlet 134.

As illustrated in FIG. 3, each microchannel 128 is a tube with arectangular cross-section through which the second fluid can flow. Theplurality of microchannels 128 may have other cross-sections (e.g.,round). As the second fluid passes through the plurality ofmicrochannels 128, the second fluid absorbs heat from the first fluidthat flows around the plurality of microchannels 128 through gaps 136.As the first fluid continues to flow around heat exchanger 112,particulate matter collects on a first side 138 of heat exchanger 112.In order to limit build up of particulate matter on first side 138, adirection of flow of the first fluid through canister 114 can bereversed using reversing valve 202. Flow of the first fluid is reversedby changing the orientation of reversing valve 202 from theconfiguration shown in FIG. 2A to the configuration shown in FIG. 2B.

Reversible flow heat exchange system 200 provides several benefits oversystem 100. For example, reversing the flow of the first fluid throughcanister 114 flushes particulate matter from gaps 136 and from firstside 138, improving efficiency of heat exchanger 112. The direction offlow of the first fluid can be reversed in a periodic fashion toincrease the time between servicing. For example, the first fluid can bepassed through canister 114 with reversing valve 202 oriented as shownin FIG. 2A for a first time interval. At the end of the first timeinterval, reversing valve 202 is adjusted to the orientation shown inFIG. 2B and the first fluid is passed through canister 114 in thereverse direction for a second time interval. This process can berepeated to reduce the build up of particulate matter upon heatexchanger 112. The first and second time intervals can be varied asdesired. For example, the first and second time intervals can be hourly,daily, weekly, monthly, etc. The first and second time intervals can bethe same time interval or different time intervals. In some aspects, thefirst and second time intervals depend upon the type of first fluidused, the type of machine 102, the characteristics of the particulatematter, and the like.

Orientation of reversing valve 202 can be done manually or can beautomated. Automation of reversing valve 202 can be implemented with acontroller 220 and an actuator 222. Controller 220 can include a CPU 224and memory 225 and is configured to control reversing valve 202. Forexample, controller 220 can be configured with a timer to set the firstand second time intervals. Actuator 222 is communicatively coupled(e.g., wired or wireless connection) with controller 220 and cancomprise various types of actuators, including servos and the like.

Automation of the orientation of reversing valve 202 can also include asensor 226 that is communicatively coupled (e.g., wired or wirelessconnection) to controller 220 and detects an amount of particulatematter that has settled on heat exchanger 112. Responsive to adetermination that a threshold amount of particulate matter has formed,controller 220 reverses flow of the first fluid through canister 114with reversing valve 202. Sensor 226 can be an optical sensor or aresistivity sensor.

An additional benefit of the reversible design disclosed herein is that,when heat exchanger 112 is a microchannel heat exchanger, theperformance of heat exchanger system 104 is not affected when the flowdirection of the first fluid is reversed. Compared to other heatexchange systems, cooling performance of reversible flow heat exchangesystem 200 is maintained regardless of the direction of the flow of thefirst fluid through canister 114. For example, if a counter-flow heatexchanger where used instead of heat exchanger system 104, reversing theflow of the first fluid would result in a reduction of coolingefficiency due to the change from counter-flow of the first fluidrelative to the second fluid to parallel-flow of the first fluidrelative to the second fluid. Furthermore, the direction of flow of thefirst fluid through machine 102 remains constant, which allows operationof machine 102 to be maintained without any operational or structuralchanges. Maintaining the performance of heat exchanger 112 is alsoimportant when the second fluid is a refrigerant. This is importantbecause it allows the refrigerant to be maintained in a superheatcondition regardless of flow direction of the first fluid. If adifferent type of heat exchanger other than a microchannel heatexchanger were used, the performance of the heat exchanger would changewhen the direction of the flow of the first fluid is changed. Changingthe performance of the heat exchanger would likely result in therefrigerant dropping out of superheat conditions, which would result ina combination of liquid refrigerant and vaporized refrigerant that coulddamage a compressor of cooling system 106.

FIG. 4 is a flowchart illustrating a method 400 of using reversing valve202 in accordance with aspects of the disclosure. FIG. 4 is discussedrelative to FIGS. 2A-3 above. Method 400 begins at step 402. At step404, machine 102 of reversible flow heat exchange system 200 beginsoperating. During step 404, reversing valve 202 is oriented asillustrated in FIG. 2A and the first fluid flows from first side 120 ofheat exchanger 112 to second side 122 of heat exchanger 112. Method 400then proceeds to step 406.

At step 406, a determination is made as to whether or not reversingvalve 202 should be reversed. The determination may be made by anoperator (e.g., a human) of reversible flow heat exchange system 200 orby controller 220. As discussed above, the decision to reverse theorientation of reversing valve 202 may be made based upon variousconsiderations. For example, the decision may be based upon an amount oftime machine 102 has been operating or an amount of debris or buildupthat has settled on first side 120 of heat exchanger 112 (e.g., byvisual inspection by the operator or as detected by sensor 226). If adetermination is made that reversing valve 202 does not need to bereversed, method 400 proceeds to step 412 and reversible flow heatexchange system 200 continues operation. If a determination is made thatreversing valve 202 should be reversed, method 400 proceeds to step 408.

At step 408, the orientation of reversing valve 202 is changed to theposition shown in FIG. 2B and the first fluid flows from second side 122of heat exchanger 112 to first side 120 of heat exchanger 112. In someembodiments, the orientation of reversing valve 202 may be changedmanually by the operator. In some embodiments the orientation ofreversing valve 202 may be changed by controller 220. For example,controller 220 may send a signal to actuator 222 to reorient reversingvalve 202. Method 400 then proceeds to step 410.

At step 410, machine 102 continues operating and the first fluid flowsthrough canister 114 in a direction opposite to the direction of flow instep 404. Method 400 then proceeds to step 412. At step 412, adetermination is made as to whether or not machine 102 should continueto operate. The determination may be made by the operator or controller220. If a determination is made to continue operation of machine 102,method 400 returns to step 406. If a determination is made to ceaseoperation of machine 102, method 400 proceeds to step 414 and method 400ends.

In this patent application, reference to encoded software may encompassone or more applications, bytecode, one or more computer programs, oneor more executables, one or more instructions, logic, machine code, oneor more scripts, or source code, and vice versa, where appropriate, thathave been stored or encoded in a computer-readable storage medium. Inparticular embodiments, encoded software includes one or moreapplication programming interfaces (APs) stored or encoded in acomputer-readable storage medium. Particular embodiments may use anysuitable encoded software written or otherwise expressed in any suitableprogramming language or combination of programming languages stored orencoded in any suitable type or number of computer-readable storagemedia. In particular embodiments, encoded software may be expressed assource code or object code. In particular embodiments, encoded softwareis expressed in a higher-level programming language, such as, forexample, C, Python, Java, or a suitable extension thereof. In particularembodiments, encoded software is expressed in a lower-level programminglanguage, such as assembly language (or machine code). In particularembodiments, encoded software is expressed in JAVA. In particularembodiments, encoded software is expressed in Hyper Text Markup Language(HTML), Extensible Markup Language (XML), or other suitable markuplanguage.

Depending on the embodiment, certain acts, events, or functions of anyof the algorithms described herein can be performed in a differentsequence, can be added, merged, or left out altogether (e.g., not alldescribed acts or events are necessary for the practice of thealgorithms). Moreover, in certain embodiments, acts or events can beperformed concurrently, e.g., through multi-threaded processing,interrupt processing, or multiple processors or processor cores or onother parallel architectures, rather than sequentially. Although certaincomputer-implemented tasks are described as being performed by aparticular entity, other embodiments are possible in which these tasksare performed by a different entity.

Conditional language used herein, such as, among others, “can,” “might,”“may,” “e.g.,” and the like, unless specifically stated otherwise, orotherwise understood within the context as used, is generally intendedto convey that certain embodiments include, while other embodiments donot include, certain features, elements and/or states. Thus, suchconditional language is not generally intended to imply that features,elements and/or states are in any way required for one or moreembodiments or that one or more embodiments necessarily include logicfor deciding, with or without author input or prompting, whether thesefeatures, elements and/or states are included or are to be performed inany particular embodiment.

While the above detailed description has shown, described, and pointedout novel features as applied to various embodiments, it will beunderstood that various omissions, substitutions, and changes in theform and details of the devices or algorithms illustrated can be madewithout departing from the spirit of the disclosure. As will berecognized, the processes described herein can be embodied within a formthat does not provide all of the features and benefits set forth herein,as some features can be used or practiced separately from others. Thescope of protection is defined by the appended claims rather than by theforegoing description. All changes which come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

What is claimed is:
 1. A reversible flow heat exchange system, thereversible flow heat exchange system comprising: a heat exchanger systemcomprising: a canister configured to receive a first fluid from amachine; and a heat exchanger disposed within the canister; a coolingsystem coupled to the heat exchanger and configured to circulate asecond fluid between the heat exchanger system and the cooling system; areversing valve coupled to the heat exchanger and configured toselectively direct a flow of the first fluid in a first directionthrough the canister and in a second direction through the canister thatis opposite the first direction; wherein the reversing valve comprises afirst pair of valve openings and a second pair of valve openings, eachpair of valve openings is coupled together such that the first fluidflows from one opening of the pair of valve openings to another openingof the pair of valve openings; wherein the first pair of valve openingscomprises a first opening and a second opening and the second pair ofvalve openings comprises a third opening and a fourth opening; andwherein the first fluid flows in the first direction for a first timeinterval and flows in the second direction for a second time interval,wherein the first time interval is different from the second timeinterval, wherein the first and second time intervals depend upon a typeof the first fluid used in the reversible flow heat exchange system. 2.The reversible flow heat exchange system of claim 1, wherein, when thereversing valve is configured to direct the first fluid in the firstdirection, a fluid outlet of the machine is coupled to the first pair ofvalve openings and a fluid inlet of the machine is coupled to the secondpair of valve openings.
 3. The reversible flow heat exchange system ofclaim 1, wherein, when the reversing valve is configured to direct thefirst fluid in the second direction, a fluid outlet of the machine iscoupled to the second pair of valve openings and a fluid inlet of themachine is coupled to the first pair of valve openings.
 4. Thereversible flow heat exchange system of claim 1, wherein the reversiblevalve is configured so that a direction of flow of the first fluidthrough the machine does not change when the first fluid flows in eitherthe first direction or the second direction through the canister.
 5. Thereversible flow heat exchange system of claim 1, further comprising anactuator coupled to the reversing valve and configured to direct thefirst fluid to flow in the first or second directions through thecanister.
 6. The reversible flow heat exchange system of claim 5,further comprising a controller coupled to the actuator.
 7. Thereversible flow heat exchange system of claim 6, wherein the controlleris configured to automatically actuate the reversing valve after apredetermined time interval.
 8. The reversible flow heat exchange systemof claim 6, further comprising a sensor associated with the heatexchanger and configured to detect build up of particulate matter on theheat exchanger.
 9. The reversible flow heat exchange system of claim 8,wherein the controller is configured to automatically actuate thereversing valve responsive to detected build up of particulate matter.10. The reversible flow heat exchange system of claim 1, wherein thereversing valve is configured for manual actuation by a user.
 11. Thereversible flow heat exchanger system of claim 1, wherein the secondfluid comprises a refrigerant.
 12. The reversible flow heat exchangersystem of claim 1, wherein the heat exchanger is a microchannelevaporator.
 13. A method of controlling a direction of fluid flowthrough a heat exchanger system, the method comprising: circulating afirst fluid between a machine and the heat exchanger system; circulatinga second fluid between the heat exchanger system and a cooling system;directing a flow of the first fluid through the heat exchanger system ina first direction by orienting a reversing valve in a first orientationand directing the flow of the first fluid through the heat exchangersystem in a second direction by orienting the reversing valve in asecond orientation, wherein the reversing valve comprises a first pairof valve openings and a second pair of valve openings, each pair ofvalve openings is coupled together such that the first fluid flows fromone opening of the pair of valve openings to another opening of the pairof valve openings, wherein the first pair of valve openings comprises afirst opening and a second opening and the second pair of valve openingscomprises a third opening and a fourth opening; exchanging, via a heatexchanger of the heat exchanger system, heat between the first fluid andthe second fluid; wherein a direction of flow of the first fluid throughthe machine remains the same when the first fluid flows through the heatexchanger system in the first or the second directions; and wherein thefirst fluid flows in the first direction for a first time interval andflows in the second direction for a second time interval, wherein thefirst time interval is different from the second time interval, whereinthe first and second time intervals depend upon a type of the firstfluid used in the reversible flow heat exchange system.
 14. The methodof claim 13, wherein the heat exchanger system comprises a canister thathouses the heat exchanger and is configured to receive the second fluidso that the second fluid flows around the heat exchanger as the firstfluid flows through the canister.
 15. The method of claim 13, whereinthe heat exchanger system comprises a controller configured to operatean actuator coupled to the reversing valve and orienting the reversingvalve comprises actuating the actuator via the controller.
 16. Themethod of claim 15, further comprising a sensor coupled to thecontroller and positioned to monitor build up of particulate matter onthe heat exchanger.
 17. The method of claim 16, wherein the controlleris configured to automatically actuate the reversing valve responsive tothe controller detecting build up of particulate matter.
 18. Areversible flow heat exchange system, the reversible flow heat exchangesystem comprising: a heat exchanger system comprising: a canisterconfigured to receive a first fluid from a machine; and a heat exchangerdisposed within the canister; a cooling system coupled to the heatexchanger system and configured to circulate a second fluid between theheat exchanger system and the cooling system; a reversing valvecomprising a first pair of valve openings and a second pair of valveopenings, wherein the reversing valve is coupled to the heat exchangerand configured to selectively direct a flow of the first fluid in afirst direction through the canister and in a second direction throughthe canister, wherein the first fluid flows in the first direction for afirst time interval and flows in the second direction for a second timeinterval, wherein the first time interval is different from the secondtime interval, wherein the first and second time intervals depend upon atype of the first fluid used in the reversible flow heat exchangesystem; wherein the first pair of valve openings comprises a firstopening and a second opening and the second pair of valve openingscomprises a third opening and a fourth opening; an actuator coupled tothe reversing valve and configured to control an orientation of thereversing valve; a controller configured to operate the actuator; and asensor coupled to the controller and positioned to monitor build up ofparticulate matter on the heat exchanger.